New fabrication techniques for high quality photonic crystals

We have developed new methods for the fabrication of high quality two-dimensional ~2D! and three-dimensional ~3D! photonic crystals. These techniques involve anisotropic etching and steam oxidation of AlAs mask layers. We have made manufacturable 2D photonic crystals with high aspect ratios for use as micropolarizers and have measured extinction ratios larger than 800 to 1 between TE and TM modes transmitted through these structures. The new Al2O3 mask fabrication technique also allows us to fabricate 3D structures with up to six repeating layers in depth and over 90% attenuation in the band gap region. Here, we show the fabrication details and performance of 2D and 3D photonic crystals. © 1997 American Vacuum Society. @S0734-211X~97!12006-6#